Fuel injection system



Dec. 6, 1938. w. G. GERNANDT FUEL INJECTION SYSTEM Filed March 15, 1937 2 Sheets-Sheet l FIG.

FIG.. 3.

INVENTORI ATTORNEY Jn. I A. d Y

r x E M y mm Em. Gm .N G .I .L E W u F Filed March l5, 19157 `2 Sheets-Sheet 2 FIGS.

FIGS,

INVENTOR: VVALD@ G. GERMAN DT ATTORNEY Patented Dec. 6, 1938 UNITED STATES PATENT OFFICE FUEL INJECTION SYSTEM Waldo G. Gernandt, Berkeley, Calif.

Application March 15, 1937, Serial No. 130,919

' 5 Claims.

This invention relates to improvements in fuel injection systems, more particularly for Diesel motors.

and entitled Engines.

Among the objects of this invention complish uniformity in the quantity, pressure, and timing of fuel distributed to the several cylinders of a multicylinder motor.

Another object is to combine the fuel pump and the fuel distributor to establish precision in the coordination of these mechanisms.

Another object is to preheat the fuel injected into the motor.

Another object is to terminate the injection is to accycle sharply so as to obviate dripping of fuel at the injector.

Another object is to provide a fuel pump of simpler and less expensive construction. Other objects and advantages appear as this description progresses.

In this specification and the accompanying drawings the invention is disclosed in its preferred form. It is, however, to be understood that it is not limited to this form because it may be embodied in other forms within the Fig. 2 is a side elevation of the same, broken away in parts to disclose the underlying structure.

Fig. 3 is a horizontasecticn taken along the line III-r-III in Fig. 1 viewed in the direction of the arrows and illustrating the distributor head.

The pump plunger is superimposed in dotted lines to show its operative relation with the distributor head.

Fig. 4 isa fragmentaryy vertical section taken along `the line IV-IVin Fig. 2 showing `the passage for 4admitting gas to the fuel pump.

Fig. 5 is a similarsectionltakenalong the line V--V in Fig. 1 and showing the engagement between `the pump `plunger yand the operating rocker arms.

6 is a diagrammatic vertical section of one of the associated motor cylinders with its fuel injector lmodifiedin accordance with the present' invention.

'j Fig. 'is` a somewhat ,enlarged viewfofanother type of fuel injector suitable forllse in tion with libe. vrsfmiievetibnif conjunc- In detail, the structure illustrated in the drawings, referring more particularly to Fig. 1 comprises the pump body I having the hollow cylinder 2 rotatable therein within the bearing 3. The cylinder 2 has the lateral flange 4 at its upper end supported by thering 5. The annular spacer 6 confines the flange 4 against lateral movement and has the distributor head 'l superimposed thereon which is in sliding contact with the rotating iiange 4. The pins 8-8 fixed in the v body I secure the head 1 against rotary movement. The ring 5, the spacer 6, and the head 1 are clamped on the body I by the nut 9 threaded on the body I at IIJ and having the flange II engaging over the top of the head 'I. The nut 9 has the spaced lugs I2 thereon to receive a suitable lwrench for turning.

The transverse shaft I3 is rotatably mounted in the body I in the bearings I4 and I5. It has the tapered shank I6 adapted to receive a suitable gear or coupling for driving the shaft. The shaft is preferably driven at the speed of the motor crankshaft. It may, however, be driven at onehalf motor speedv by slightly modifying the structure to be later described as will be obvious to those skilled in the art.

The spiral pinion I1 is fixed on the shaft I3 and is enmeshed with the spiral gear I8 provided at the lower end of the cylinder 2. The angle of the spiral of the gears II-IB is designed so that the cylinder 2 is rotated at one-half the speed of the shaft I3.

'I'he pump plunger I9 is slidable within the cylinder 2. Its lower portion is cut away to form the recess 20. .The rocker arm 22 located at one side of the gear I'I has the integral hub 23 fixed on the shaft 24 which is rotatably mounted in bearings such as 25. 'I'he end of the rocker arm is slightly offset and rounded off at 26 and operatively engages the recess 20 in the plunger I9, see Fig. 5.` l

'Ihe roller 21 is provided on the loppositeend of the rocker arm`22 and cooperates witlithe cam'ZB. The rises29 displace the' roller 2l to operatively raise the plunger I9 into the position shown. The rises are timed to coordinate the movements of the yplunger I9 with the timing groove 32 therein, see also Figs. 2 and 3. The passage 33 leads downward from the groove 32 to the rotatable fuel supply sleeve 34. The port 35 regulates the amount of fuel supplied by the extent of its registry with the passage 33. The throttle lever 3B enables the sleeve 34 to be rotated to adjust the fuel supply as desired'. The feed groove has the short radial channels 31 leading therefrom. The flange 4 has the channel 38 therein which is arranged to register successively with each of the channels 31 to supply the interior of the cylinder 2 with fuel.

The leads 39 in the head 1 are spaced a predetermined distance from the channels 31 and are arranged to register with the channel 38 after it has passed from communication with the channels 31. The leads 39 are connected by means later described, to a supply of a suitable compressed gas. This gas is admitted through the channel 31 into the pump cylinder 2 and mixes with the fuel previously introduced thereinto. In the present instance compressed air from the motor cylinders is utilized. Obviously, however, some other gas such as pure oxygen could be mixed with the fuel charge.

The outlets 40 in the head 1 register with the channel 38 on the delivery stroke of the pump plunger I9. 'Ihe outlets are connected to injectors in the motor cylinders by the tubes 4|. The ends of the tubes 4| are welded in the unions 42 which have the lateral flanges 43. The nuts 44 threaded in the distributor head 1 engage the flanges 43 to force the unions 42 into firm engagement with the head 1. The gaskets 45 are interposed between the unions 42 and the head. The passages 46 lead from the outlets 40 through the head 1, the gaskets 45, and the unions 42 to the tubes 4I.

The conduits 41 surround the tubes 4| and are similarly welded to the unions 42. The annular space within the conduits is connected to the leads 39 by the passages 48, see Fig. 4, provided through the unions 42, the gaskets 45 and the head 1.

Fig. 6 shows one cylinder and the associated fuel injector of the multicylinder motor in conjunction with which the present invention is used. Since all the cylinders are alike in construction and operation, only one is illustrated and described.

The construction comprises the cylinder 50 surrounded by the usual water jacket 5|. 'Ihe head 52 closes the cylinder 50 and has the water jacket 53. The piston 54 operates in the cylinder 50 and is operatively connected to the crank shaft of the motor in the usual manner.

The injector 55 is secured in the opening 56 in the head 52 by the clamp 51 and the bolt 58. The gasket 59 interposed between the injector and the shoulder 60 in the opening 56 prevents gas leaks past the injector. The tube 4| and its enclosing conduit 41 have their ends xed in the union 6| which is similar in all respects to the unions 42 previously described. The coupling 62 secures the union 6| to the injector 55.

The injector has the central passage 63 therein which communicates with the interior of the tube 4I. The restricted orifices 64 discharge `from the lower end of the passage 63 into the cylinder 50. The injector also has the passage 65 therein communicating with the interior of the cylinder gases from the motor cylinder 50 to the space Within the conduit.

A modied form of injector is illustrated in Fig. 7. In this form, the injector 'IIJ has the central passage 1I enlarged at 'I2 to receive the needle valve 13 which seats at 14 to close the passage 1|. The needle valve is normally seated by the spring 15 expanding thereagainst. The setscrew 16 is adjustable to regulate the tension of this spring. The bypass 11 connects the passage 1| to the fuel tube 4|.

'I'he pressure of the fuel beneath the needle valve 13 during the injection cycle unseats the valve and permits the flow of fuel through'the passage 1I. When the fuel pressure diminishes at the end of this cycle, the spring 15 seats the valve 13 sharply terminating the flow of fuel and preventing dripping from the injector as usual in this type of injector.

The passage 18 communicates with the motor cylinder through the bottom of the injector and discharges into the enlarged portion 12 of the central passage above the needle valve 13. The short passage 19 leads from this portion 12 to the annular space Within the conduit 41. Any leakage of fuel above the stem of the valve 13 is thus conveyed back to the fuel pumpthrough the passage 19 and the conduit 41.

The apparatus operates substantially as follows: When the rise 29 of the cam passes the roller 21, the spring 33 expands and lowers the pump plunger I9. The sleeve 2 is continuously rotated by the driving gear I1. This rotation. brings the channel 38 into registry with the fuel channel 31 during initial portion of the above described downward stroke of the plunger. Fuel then flows into the space above the descending plunger I9. The amount of the fuel admitted depends upon the extent of the registry of the regulating port 35 with the intermediate fuel passage 35, see Fig. 2. The channel 38 passes from registry with channel 31 while the plunger I9 is still executing its downward stroke.

The continued rotation of the cylinder 2 carries the channel 38 into registry with the lead 39. The piston 54 in the cylinder 50, see Fig. 6, into which the fuel charge is to be subsequently injected, is simultaneously executing its compression cycle. Air thus compressed in the cylinder 50 flows upward through the passage 65 into the annular space within the conduit 41. From thence, it passes through the passage 48, the lead 39, and the channel 38 into the pump cylinder 2 above the plunger I9. The continued downward movement of the plunger aids in this transfer of air from the cylinder 50 to the pump cylinder 2. The channel 38 passes from registry with the lea'd 39 after the plunger I9 terminates its downward movement. This outs off all communication from the pump cylinder 2.

The upward stroke of the pump plunger I9 is accomplished by the rise 29 of the cam displacing the roller 21. The mixture of fuel and air above the plunger is compressed until it reaches the usual injection pressure. The internal heat of the compressed air raises the temperature of the fuel mixture to near the ignition temperature at the given pressure. When the fuel mixture reaches the above pressure, the channel 38 passes into registry with the outlet 40. The fuel mixture then flows through the passage 46, the tube 4I, and the injector 55 and is injected into the motor cylinder through the orifices 64. The operation of the pump is coordinated with the motor so as to commence injection at the usual point in the cycle of operation of the motor cylinder.

The flow of compressed air through the conduit 4l immediately preceding the injection cycle, as hereinbefore described, preheats the tube 4| and surounds it against loss of heat by an insulating blanket of hot air. The fuel charge is thus injected into the Water cylinder at nearly the temperature to which it was raised in the pump cylinder, thus promoting combustion.

At the end of the injection cycle, the plunger i9 begins its downward movement just before the channel 38 passes from registry with the outlet All. This relieves the pressure in the passages leading to the injector thus sharply terminating the injection cycle and obviating any subsequent slow dripping of fuel from the injector.

The channel 38 next passes into registry with the succeeding fuel supply channel 37. The cycle of operation of the pump is then repeated and fuel injected into another cylinder of the motor.

Having thus described this invention, what is claimed and desired to secure by Letters Patent l. A fuel pump for internal combustion motors including a body having a pump chamber therein; a plunger slidable in said chamber; means for reciprocating said plunger; a distributor head xed on said -body and having therein a fuel supply groove, a lead communicating with a source' of compressed gas, and an outlet communicating with a fuel injector; a member rotatably mounted in said body in slidable engagement with said head and having a channel therein communicating with said pump chamber and adapted to register successively With said fuel supply groove, said gas lead, and said injector outlet; and means for driving said rotatable member intimed relation to said reciprocating plunger so that said i channel registers with said fuel supply groove and said gas lead during the intake stroke of said plunger and with said injector outlet during the discharge stroke of the plunger.

2. A fuel pump for internal combustion motors including a body; a hollow cylinder rotatably mounted in said body and having a radial channel therein communicating with the interior of the cylinder; a plunger slidably mounted within said cylinder; means for reciprocating said plunger; a distributor head slidably, engaging that portion of said cylinder having said channel therein and having therein a fuel. supply groove, a lead communicating with a source of compressed gas, and an outlet communicating with a fuel injector; and means for rotating said cylinder in timed relation to said reciprocating plunger; said channel being brought, by the rotation of said cylinder, in@ registry with said fuel supply groove and said gas lea`d successively during the intake stroke of said plunger and said injector outlet during the discharge stroke of said plunger.

3. In a multi-cylinder internal combustion motor; a fuel pump including a body; a hollow cylinder rotatably mounted in said body and having a radial channel therein communicating with the interior Iof the cylinder; a plunger slidably mounted within said cylinder; means for reciprocating said plunger; a distributor head slidably engaging that portion of said cylinder having said channel therein and having a plurality of equiangularly spaced outlets communicating with fuel injectors associated with the cylinders of said motor, leads spaced a predetermined angular distance from each of said outlets and communicating with a source of compressed gas, and a fuel supply groove having channels spaced a predetermined distance frorn each of said leads; and means for rotating said cylinder in timed relation to said reciprocating plunger; said radial channel being brought, by the rotation of said cylinder, into registry with one of said fuel channels, and the adjoining gas lead successively during the intake stroke of said plunger and the adjacent injector outlet during the discharge stroke of said plunger.

4. In combination with a cylinder of an internal combustion motor; a fuel injector associated with said cylinder; a fuel pump having a chamber therein and an outlet, a lead, and a fuel supply means, all normally sealed from said chamber; a plunger slidably mounted in said chamber; means for reciprocating said plunger; a tube connecting said outlet to said injector; a conduit enclosing said tube and providing communication between said lead and the interior of said cylinder; and means for providing communication, between said fuel supply means and chamber on the initial portion of the downward stroke of said plunger, between said lead and said chamber on the latter portion of said downward stroke of the plunger, and between said outlet and said chamber on the upward stroke of the plunger.

5. A fuel pump for internal combustion motors including a body; a hollow cylinder rotatably mounted in said body and having a lateral flange `thereon with a radial channel therein communicating with the interior of the cylinder; means for rotating said cylinder; a distributing head fixed on said body slidably engaging said flange and having therein, a fuel supply groove, a gas supply lead, and an outlet, all arranged to register with said channel in succession as said cylinder rotates; a plunger slidable in said cylinder; a rocker arm operatively engaging the end of said plunger; and a cam arranged to oscillate said rocker arm so as to reciprocate said plunger in timed relation to the rotation of said cylinder so that said channel registers wzth said fuel supply groove and said gas lead during the intake stroke of said plunger and with said outlet during the discharge stroke of the plunger.

WALDO G. GERNANDT. 

